"His life was one of love, optimism, joy, humor, and compassion, and this page is to celebrate that life," she wrote.

Guha returned from a trip to India last year with a stomach ache and only one month later learned he had stage-4 colon cancer. Aetna agreed to full coverage for his treatment, but the aggressive cancer returned in the fall.

"He ran out of treatment options," the close friend said. "He'd been in hospice care for many months."

Guha died at home, Ehlers said.

"My heart is aching, but the pain is eased a bit knowing that he has the support of such an amazing community of people, so many of whom have never met him," she said on the tribute page today."

After getting his tough diagnosis, Guha faced hundreds of thousands of dollars in medical bills.

He had a policy under the university's health plan for which he paid $400 a month out of pocket, but its carrier, Aetna, had an annual ceiling on payouts. After surgery and chemotherapy, he had exhausted the lifetime $300,000 limit.

[The Affordable Health Care Act has since eliminated lifetime limits, but then, it did not include student health plans.]

Outraged, Guha turned to Twitter and other social media to make his case.

But in August, Aetna CEO Mark T. Bertolini, a former paramedic who has had his own share of medical crises, tweeted directly with Guha and agreed to pay "every last penny" of his bills.

"The system is broken, and I am committed to fixing it," Bertolini said on his Twitter account. "I am glad we connected today and got this issue solved. I appreciate the dialogue no matter how pointed. I've got it and own it!"

It turns out Bertolini and Guha had much in common.

In 2001, Bertolini's son, Eric, then 16, was diagnosed with a rare and deadly lymphoma, according to a profile in the Hartford Courant. And in 2004, when he was president of Cigna, Bertolini was disabled after being nearly killed in a ski accident. He also eventually donated a kidney to help save his son.

Bertolini admitted that the health care system was "broke" and tweeted, "There is a lot to do to make it right."

Meanwhile, Guha had raised $120,000 through T-shirt sales in his edgy campaign "Poop Strong," which riffed on cancer survivor Lance Armstrong's "Live Strong." And when Aetna stepped in, Guha said he would donate all of it to three cancer charities in Arizona.

Colorectal cancer is the second-leading cancer killer in the United States, according to the Centers for Disease Control and Prevention. In 2008, the last year for which there are statistics, 142,950 Americans were diagnosed with colorectal cancer and 52,857 Americans died from the disease.

Surprisingly, colorectal cancer is not that uncommon among younger people like Guha, especially those who have a family history of early-onset disease.

Symptoms can include rectal bleeding or anemia, abdominal pain or occult blood in the stool.

Such was the case with Guha, who was diagnosed in February 2011. He had settled in Phoenix with his wife and was getting a doctorate in environmental sustainability. The couple returned from a trip to India to visit his relatives and Guha developed abdominal pain.

"It seemed like the standard sort of bug issue when I get back from India," he told ABCNews.com at the time. "But it continued and got different, to the point where I was doubled up on the floor, and I was having trouble eating."

Because of his age, doctors never suspected cancer and looked at every other possibility, "including the plague," Guha said.

A battery of tests were negative, but eventually a colonoscopy revealed a 6 cm.-wide tumor in the sigmoid colon.

When he saw a report that suggested it was malignant, Guha said, "I was in denial. I thought surely there was another explanation."

MRIs and surgery revealed that the cancer had proliferated into his entire abdominal cavity: a stage-4 diagnosis. "It was pretty dire," he said.

Guha had a colostomy, conventional chemotherapy, the removal of his gall bladder and a heated chemo bath of the lining of his stomach, as the medical bills mounted.

By the time Guha had exhausted his insurance benefits, he had about $118,000 in medical bills.

For a time, he dedicated himself to fundraising for more support for cancer patients and their families, especially Arizona's undocumented, who have no insurance.

"I could never get through life like that or be a productive member of society," he said then. "I have always dedicated my life to doing something useful."